Network analysis of different exogenous hormones on the regulation of deep sowing tolerance in maize seedlings

The planting method of deep sowing can make the seeds make full use of water in deep soil, which is considered to be an effective way to respond to drought stress. However, deep sowing will affect the growth and development of maize (Zea mays L.) at seedling stage. To better understand the response of maize to deep-seeding stress (DS) and the mechanism of exogenous hormones (GA, BR, SL) alleviates the damaging effects of DS, the mesocotyl morphology, and transcriptome expression profiles of seedlings of deep-seeding sensitive inbred line Zi330 and the deep-tolerant inbred line Qi319 were compared under DS and the conditions of exogenous hormones alleviates stress.Transcriptome analysis showed that the differentially expressed genes (DEGs) of Qi319 and Zi330 mainly enriched in the redox process, and the functions related to the plasma membrane and cell wall tissue under DS. The deep seeding stress was alleviated by GA, BR and SLs, the DEGs mainly includes cellulose synthase, expansin and glucanase, oxidase, lignin biosynthesis genes and so on. In addition, we found that protein phosphatase 2C and GA receptor GID1 enhanced the ability of resist deep seeding stress in maize by participating in the ABA and the GA signaling pathway. Through WGCNA analysis, some core genes in the modules that significantly related to mesodermal elongation were identified. 10 genes were verified by qRT-PCR, and their expression results were basically consistent with the transcriptome expression profile. Our results from this study may provide theoretical basis for determining the maize deep seeding tolerance and the mechanism by which exogenous hormones regulates deep seeding tolerance.